The resignation of McEnroe, one of the greatest players in Davis Cup history, comes nearly four months after the team was swept by Spain in the semifinals.
McEnroe, in a statement released by the U.S. Tennis Association, said he was "extremely frustrated with the difficulties of the scheduling and format of the competition."
He also was troubled because two of the world's top players Pete Sampras and Andre Agassi were unwilling to fully commit to Davis Cup play.
"I was privileged to have been selected and honored to have served as captain," McEnroe said. "Unfortunately, for a variety of reasons, I was disappointed that I was unable to have a great impact as captain of the team."
McEnroe was appointed captain on Sept. 8, 1999, a move designed to pump life into an event that does not get nearly as much attention in the United States as it does around the world.
He immediately received a call from Agassi, who said he wanted to be on the team. After much pleading, McEnroe also got Sampras to come aboard. But he pulled out of the first-round series against Zimbabwe, citing an injury.
Agassi won the Australian Open and then flew to Zimbabwe, leading the United States to a narrow victory over the African nation.
Agassi and Sampras showed in Los Angeles for the next round. Still, the Americans barely edged the Czech Republic.
However, the two skipped the semifinals on clay in Spain because of injuries. McEnroe put together a makeshift team, but the Americans failed to win a match in three days.
It was the first time in 101 years of Davis Cup play that the United States was beaten 5-0 without the title on the line.
"I'm totally spent, I'm deflated," McEnroe said at the time.
Signing for three years as captain, McEnroe was set on restoring the lost glory of Davis Cup in the United States. In the 1920s, '30s and '40s, the Davis Cup was among the biggest events on the American sports calendar, rivaling any of the majors.
McEnroe brought back some of its popularity in the late 1970s and early '80s, when he helped win four championships in five years. As captain, he thought his name and status and love of the cup would lure the top players.
"Either it's bad luck or I haven't made a difference," McEnroe said at the start of the semifinals in Spain. "I'm not sure what it is at this point. Obviously, one of the reasons I was hired was so that I would make a difference in getting the players to play. Well, I clearly haven't succeeded. I'd like to think it's bad luck."
McEnroe insisted that the DaviCup need to change its schedule. He thought a month should be set aside for the tournament, creating a "Davis Cup time" that players and fans could easily identify.
"I have made it known for many years that the current format is problematic for the world's top players," he said.
While he stressed that his job was to win the Davis Cup title, he pointed to the organizational obstacles.
"It is my hope that the Davis Cup will be restructured so that it can be everything I envision it has the potential to be," he said.
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